If the elements are working they will be warm to the touch with ignition on. The length of time it takes for the chokes to open depends on how the chokes have been set. the is a dimple on the edge of the choke element and a dimple on the edge of the carb were the element fits. I have found if you align these 2 dimples up then there is too much choke and it takes too long for the choke to be in the off position. You can tell if there is too much choke because when you press the closed choke flap with your finger there will be too much tension on it. (Tested cold)
Does it really run out or just read zero fuel level at some point? See how far it goes before it really runs out. Carry a 5 litre can full of petrol to top up. If nothing is wrong it should go 240 miles (12 galls @ 20 mpg) at least. I think @andyv mentioned a dodgy fuel gauge. Might this problem really be as simple as a worn sender that under reads when cold or a dashboard voltage stabiliser that goes low when it is cold. A sticky choke would tend to make plugs go blacker. Before going off on a rant about the mystical properties of some new petrol additive (ethanol) that magically targets one bus with an intermittent problem that others do not see, look first to simple local (electrical/wear and tear) faults.
Yep, definitely what I'd expect to be getting. Maybe a tin top with just a bed in it would get a bit more, but for my Devon Moonraker, I'm ok with what I get.
Yes it really did run out, but fortunately I was in walking distance of Halfords and a petrol station next door, so I could buy a can and take it back. It had only done about 250 km. The fuel sender and stabiliser were renewed a couple of years back but the read out is very non linear. That’s the poor parts you get these days. I’ve done all sorts of experiments with this and haven’t yet got it right so have to rely on the trip meter.
I had a new replacement fuel sender for a while, load of rubbish it was, replaced it with a genuine second hand one and I've now got a pretty accurate fuel gauge.
Low 20s to the gallon I get on average. It is a two tonne bread loaf i am trying to haul along so no complaints.
Thinking about chokes, the stock carbs and my progressive all have the feature that when you run the engine fast the vacuum from the venturi in the carburettor is fed to a mechanism that pulls the choke off so if you look at plugs after a fast run you might not notice. Its the bit where you drive around slowly and the choke comes back on if the heater element is not functioning. On my old 34PICT-3 the spade terminal was loose on the heater and I had to carefully use a centre punch to re-rivet the copper rivets that connect the tag to the heating element inside.
I thought about this and have tested the resistance of the two choke units. Both are about 12 ohms and I recon if there was a break there would be a more noticeable difference. Additionally, I went for a brisk run yesterday and there was no indication of a fault - when I had this some time ago, the bus smelled of fuel when one of chokes closed up. I’m beginning to think though that this might just be the result of lots of short trips where the engine has barely warmed up. Between September and January until I took a trip to Scarborough, I’ve not been more than 10 miles at a time.
Can get to Bude in Cornwall which is 300 miles on a tank fully loaded Sent from my SM-J510FN using Tapatalk
I got a piece of paper and 28 - 30 mpg without even trying , the past is the future , write it down ( 1600 TP single Solex )
I'm still chasing this high fuel consumption but it does look like an over rich mixture if the state of my plugs is anything to go by. They are all like the one below. The choke flaps are definitely staying open, and I've optimised the idle mixture with my Gunson's Gastester, but what I've discovered is that the accelerator pumps on both sides inject a small volume of fuel into the venturi every time the accelerator pedal is pressed. This is as expected, but I had a look after a run with the engine off and there was a small constant drip of fuel from the delivery pipe. The pipe can be seen in the pic below adjacent to the choke flap. This is just for illustration and is not the carb in question. I doubt that's supposed to happen, and I presume this is constant whilst driving. Next check is the float valve levels.
